Surgical sponge and the preparation thereof



P 1952 R. H. SIFFERD EI'AL SURGICAL SPONGE AND THE PREPARATION THEREOF Filed Oct. 14, 1947 Patented Sept. 16, 1952 UN T D AT-Es PATENT: 0" -I E/iif SURGICALSPONGEANDTHE'PREPARATION mrmnaor.

and Company, Illinois Chicago, 111., 'a corporation .of

Application October 14, 1947, Serial No.,779,820

This invention relates to a surgical sponge and to the preparation thereof: The invention'is particularly useful in the preparation of a sponge from collagen, and the resulting product is'junusually'efiective as a sponge for various'types of surgical and othertechniques. v p

object of the invention is to provide a surgical sponge of sturdy and efi'ective fibrous structure which is effective as a means for stopping the fiow of blood or other fluids and which will be absorbed after a time in the body. Yet another object is to provide a new form of sponge having greater physical strength than other protein-containing sponges and of new and 'highly desirable physical structure. Yet another object is to providea method for the preparation of such sponge or sponges and in whichsimple steps are eifective'for the preparation of "the new product. Other specific objects and advantages willf appear as the specification r .y v The product embodying the invention and as produced by the process of the present invention is illustrated in the accompanying drawing, in

i I Figure 1 is a perspective view of 1 a sponge embodying our invention; Fig. 2, a greatly enlarged sectional view of a portion of the sponge; and 'Fig. 3, a perspective View of a modified form of sponge embodying our invention. Incarrying through one phase of our invention, acid collagen gel' is first prepared by any suitable method. For example, beef tendons may be cut up into small pieces and allowed "to swell in water to which an organic acid, such as dilute acetic acidfis added. 'The swollen tendons are forced through layers of stainless "steel-plates or screens under high pressure. The comminuted'material thus formed is "diluted with water andagitated. The resulting colloidal 18 Claims. (01. 12s-,-156) remains as a water-insoluble product.

suspension is centrifuged and the clarified material neutralized with ammonium hydroxide" to "precipitate the collagen. The precipitated collagen is then washed and treated with an organic acid, say, for example, malonic, acetic, formic acid, etc; The resulting; acid collagen gel is then ready for asecond {step in the process;

V Thefacid collagen gel is next sublimed' under vacuum and this step maybe carried'out with the acid collagen in any suitableconcentration.

We 'havefound that acid collagen concentrations of"% to 1.8% solids give excellent results. The

sublimation step may be done 1 either with or 'without incorporating air, and it produces a 'watensolublesponge structure."

'a'specific example, the acid collagen 'gel' within such forms.

. 2 maybe poured out in forms which'are in contact with dry ice and the gel frozeninblocks The blocks of frozen collagen gel are then dried by vacuum sublimation in the usual manner. g A p 7 The sponge produced by the above treatment may nowbe further treated to neutralize the organic acid, and preferably to remove the resulting organic salt, while also rendering the sponge water-insoluble.

The neutralizing step may be carried en in any 'suitablemanner. For example, the dehydrated acid collagen sponge may be neutralized by immersing it in a bath of ammoniaoal alcohol (2% ammonia, 98% ethyl alcohol (dry)). The ammonia salt of the organic acid dissolves in the alcohol and the neutral collagensponge It may then be washed with repeated rinsings of dry alcohol and is then ready for surgical applica tion; v H V Instead'of neutralizingwithdryammoniacal alcohoL; the water-soluble dehydrated sponge may be neutralized'byjimmersing in cold ammonium hydroxide solutionl In this-operation, the ammonia neutralizes the organic acid. The product is then washed-with water to' remove the ammonia and ammonium-organic acid salt.

'to' disintegrate in the wound after a selected desired time. I i v I Y I The-resulting sponge produced shown in Figs.

' 1 and 2 consists of a mass of interlocked collagen fibrils IB separated by channels llyas shown best in Fig. 2. Thecollagen fibrils extend in different directions and with heterogenous orientation, the fibrils being interlocked for the most part. The air channels 'l'l extend'through the masses of collagen fibrils and separate'them. The product is unusually sturdy, highly effective in preventing the flow of blood and other liquids,

while at the same time disintegrating after the same has remained in the body for a time which is predetermined through the use of tanning agents. I 'i.

The sponge so produced is'reticulated and organic acid to form a neutral and substantially water-insoluble product.

9. In a process for preparing a surgical sponge in which process collagen is precipitated from a collagen-bearing source and treated with an organic acid, the steps of freezing the acid 001- lagen gel and then subliming the water therefrom -to produce a dehydrated water-soluble sponge,

collagen-bearing source and treated with an organic acid, the steps of freezing the acid collagen gel and then subliming the'water therefrom to produce a dehydrated water-soluble sponge, neutralizing the acid to form a salt of said organic acid, removing the salt, subjecting the sponge to the action of a tanning agent to increase the resistance to body fluids, and drying the sponge.

11. In a process for preparing a surgical sponge in which an acid collagen gel is formed, the steps of freezing the acid collagen gel and then subliming the water therefrom to form a watersoluble sponge, dissolving one side of the sponge with water to form a continuous gel surface, and neutralizing said sponge.

12. In a process for preparing a surgicalsponge from an acid colagen gel, the steps of freezing the acid collagen gel and then subliming the water therefrom to produce a water-soluble sponge, applying waterto a portion only of said sponge, and neutralizing the acid of said sponge.

13. In a process for preparing a surgical sponge, the steps of preparing an acidcollagen gel, placing the gel in forms, freezing the gel to form frozen bodies thereof, and sublimating the water from the frozen bodies under vacuum to form a dehydrated water-soluble sponge.

14. In a process for preparing a surgical sponge, the steps of preparing an acid collagen gel, placing the gel in forms, freezing the gel to form frozen bodies thereof, sublimating the water from the frozen bodies under vacuum to form a dehydrated water-soluble sponge, and neutralizing the acid of said sponge.

15. In a process for preparing a surgical sponge, the steps of preparing an acid collagen gel, freezing the acid collagen gel and then subliming the water therefrom to produce a water-soluble sponge, and immersing the sponge in an ammoniacal alcohol solution.

16. In a process for preparing a surgical sponge, the steps of preparing an acid collagen gel, freezing the acid collagen gel and then subliming the water therefrom to produce a water-soluble sponge, immersing the sponge in an ammonical alcohol solution, washing the sponge, and drying the same.

17.. Ina process for preparing a surgical sponge in which collagen-bearing material is comminutecl, swollen in an aqueous suspension, and neutralized to precipitate the collagen, the steps of treating the collagen with an organic acid, freezing the resulting gel, drying the frozen gel by vacuum sublimation, and neutralizing the acid.

18. In a process for preparing a surgical sponge in which collagen-bearing material is cumminuted, swollen in an aqueous suspension, and neutralized to precipitate the collagen, the steps of treating the collagen with an organic acid, freezing the resulting gel, drying the frozen gel by vacuum sublimation, neutralizing the acid to form a water-insoluble sponge, dipping the sponge into an ammonium hydroxide solution, and washing and drying the product.

ROBERT H. SIFFERD. RALPH J. SCI-IMI'IT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 191,132 Garrison May 22, 1877 471,343 Poehl Mar. 22, 1892 582,926 Johnson May 18, 1897 652,519 OCallaghan June 26, 1900 1,548,504 Becker Aug. 4, 1921 2,166,074 Reichel July 11, 1939 FOREIGN PATENTS Number Country Date 466,064 Great Britain May 21, 1937 487,660 Great Britain June 23, 1938 OTHER REFERENCES Pilcher et al., Surg. Gyn. and Obstet.. Oct. 1945, pages 365 to 369. 

